Objective CME detection over the solar cycle: A first attempt

We recently developed a software package to autonomously detect coronal mass ejections (CMEs) in image sequences from large angle spectrometric coronagraph (LASCO). The detection is not done in the original images, instead we detect bright ridges in (time, height) plots using a modified version of the Hough transform. Experimental results on real-time data have shown that the developed technique can achieve excellent results in measuring starting time and principal angle and good results for the angular width and velocity measurement compared to the CMEs listed in the manually assembled catalog. The real-time output of the software can be found online at www.sidc.oma.be/cactus.With the present paper, we report on the first large scale application of the software to the LASCO archive. In an ongoing work, we have applied the software on a first sample of 29 months selected from archive data in the period July 1997 to December 2002. The results in this paper show that relevant characteristics of CMEs over the solar cycle are successfully recovered with the automated procedure. This proves that a completely automatically produced CME catalog is within reach.